Track where and when we acquire and release the power well for pps
access along the dp aux link, with a view to detecting if we leak any
wakerefs.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: John Harrison <John.C.Harrison@Intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190114142129.24398-18-chris@chris-wilson.co.uk
The majority of runtime-pm operations are bounded and scoped within a
function; these are easy to verify that the wakeref are handled
correctly. We can employ the compiler to help us, and reduce the number
of wakerefs tracked when debugging, by passing around cookies provided
by the various rpm_get functions to their rpm_put counterpart. This
makes the pairing explicit, and given the required wakeref cookie the
compiler can verify that we pass an initialised value to the rpm_put
(quite handy for double checking error paths).
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190114142129.24398-16-chris@chris-wilson.co.uk
Needs just a few additional includes here and there.
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Acked-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190108082709.3748-1-jani.nikula@intel.com
Do not make it an error to call intel_edp_drrs_enable while drrs has
already been enabled, instead exit silently in this case.
This is a preparation patch for ensuring that DRRS is enabled on fastsets.
Note that the removed WARN_ON could also be triggered from userspace
through the i915_drrs_ctl debugfs entry which was added by
commit 35954e88bc ("drm/i915: Runtime disable for eDP DRRS")
Reviewed-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20181220132120.15318-2-hdegoede@redhat.com
Add a fallback detection method for TypeC legacy ports in case the
VBT port information used to detect normally such ports is
incorrect.
For the fallback method we use the TypeC legacy mode specific HPD
interrupt flag which should only be raised for a legacy port.
WARN if the VBT port info is incorrect.
In a case where we'd detect the port in a contradicting way both as a
legacy and also as a USB DP and/or TBT alternate port treat the port
as legacy (by also emitting a WARN from icl_update_tc_port_type).
v2:
- Repurpose the detection as a fallback method instead of using
it only for the DP legacy case. By now we should normally use VBT to
detect DP legacy ports as well.
Suggested-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Paulo Zanoni <paulo.r.zanoni@intel.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: José Roberto de Souza <jose.souza@intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: Imre Deak <imre.deak@intel.com>
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com> (v1)
Reviewed-by: Mika Kahola <mika.kahola@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20181214182703.18865-5-imre.deak@intel.com
Atm HPD disconnect events on TypeC ports will break things, since we'll
switch the TypeC mode (between legacy and disconnected modes as well as
among USB DP alternate, Thunderbolt alternate and disconnected modes) on
the fly from the HPD disconnect interrupt work while the port may be
still active.
Even if the port happens to be not active during the disconnect we'd
still have a problem during a subsequent modeset or AUX transfer that
could happen regardless of the port's connected state. For instance the
system resume display mode restore code and userspace could perform a
modeset on the port or userspace could start an AUX transfer even if the
port is in disconnected state.
To fix this keep TypeC legacy ports in legacy mode whenever we're not
suspended. This mode is a static configuration as opposed to the
Thunderbolt and USB DP alternate modes between which we can switch
dynamically.
We determine if a TypeC port is legacy (wired to a legacy HDMI or a
legacy DP connector) via the VBT DDI port specific USB-TypeC and
Thunderbolt flags. If both these flags are cleared then the port is
configured for legacy mode.
On such legacy ports we'll run the TypeC PHY connect sequence explicitly
during driver loading and system resume (vs. running the sequence during
HPD processing). The connect will succeed even if the display is not
connected to begin with (or disappears during the suspended state) since
for legacy ports the PORT_TX_DFLEXDPPMS / DP_PHY_MODE_STATUS_COMPLETED
flag is always set (as opposed to the USB DP alternate mode where it
gets set only when a display is connected).
Correspondingly run the TypeC PHY disconnect sequence during system
suspend and driver unloading. For the unloading case I had to split
up intel_dp_encoder_destroy() to be able to have the 1. flush any
pending encoder work, 2. disconnect TC PHY, 3. call DRM core cleanup and
kfree on the encoder object.
For now run the PHY disconnect during suspend only for TypeC legacy
ports. We will need to disconnect even in USB DP alternate mode in the
future, but atm we don't have a way to reconnect the port in this mode
during resume if the display disappears while being suspended. So for
now punt on this case.
Note that we do not disconnect the port during runtime suspend; in
legacy mode there are no shared HW resources (PHY lanes) with other HW
blocks (USB), so no need to release / reacquire these resources as with
USB DP alternate mode. The only reason to disconnect legacy ports during
system suspend is that the PORT_TX_DFLEXDPPMS /
DP_PHY_MODE_STATUS_COMPLETED flag must be rechecked and the port must be
connected again during system resume. We'll also have to turn the check
for this flag into a poll, after figuring out what's the proper timeout
value for it.
v2:
- Remove the redundant special casing of legacy mode when doing a
disconnect in icl_tc_port_connected(). It's guaranteed already that we
won't disconnect legacy ports in that function.
- Add a note about the new intel_ddi_encoder_destroy() hook.
- Reword the commit message after switching to the VBT based detection.
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=108070
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=108924
Cc: Paulo Zanoni <paulo.r.zanoni@intel.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: José Roberto de Souza <jose.souza@intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: Imre Deak <imre.deak@intel.com>
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20181214182703.18865-4-imre.deak@intel.com
It's useful to see at which point a TypeC port gets disconnected, so add
a debug print for it.
Cc: Paulo Zanoni <paulo.r.zanoni@intel.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: José Roberto de Souza <jose.souza@intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: Imre Deak <imre.deak@intel.com>
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20181214182703.18865-2-imre.deak@intel.com
In August 2018 the BSPEC changed the ICL port programming sequence to
closely resemble earlier gen programming sequence. Restrict combo phy to
HBR max rate unless eDP panel is connected to port.
v2: remove debug code that Imre found
v3: simplify translation table if-else
v4: edp translation table now based on link rate and low_swing
v5: Misc review comments + r-b
BSpec: 21257
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Imre Deak <imre.deak@intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Reviewed-by: Imre Deak <imre.deak@intel.com>
Signed-off-by: Clint Taylor <clinton.a.taylor@intel.com>
Signed-off-by: Imre Deak <imre.deak@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/1545084827-5776-1-git-send-email-clinton.a.taylor@intel.com
DSC can be supported per DP connector. This patch adds a per connector
debugfs node to expose DSC support capability by the kernel.
The same node can be used from userspace to force DSC enable.
force_dsc_en written through this debugfs node is used to force
DSC even for lower resolutions.
Credits to Ville Syrjala for suggesting the proper locks to be used
and to Lyude Paul for explaining how to use them in this context
v8:
* Add else if (ret) for drm_modeset_lock (Lyude)
v7:
* Get crtc, crtc_state from connector atomic state
and add proper locks and backoff (Ville, Chris Wilson, Lyude)
(Suggested-by: Ville Syrjala <ville.syrjala@linux.intel.com>)
* Use %zu for printing size_t variable (Lyude)
v6:
* Read fec_capable only for non edp (Manasi)
v5:
* Name it dsc sink support and also add
fec support in the same node (Ville)
v4:
* Add missed connector_status check (Manasi)
* Create i915_dsc_support node only for Gen >=10 (manasi)
* Access intel_dp->dsc_dpcd only if its not NULL (Manasi)
v3:
* Combine Force_dsc_en with this patch (Ville)
v2:
* Use kstrtobool_from_user to avoid explicit error checking (Lyude)
* Rebase on drm-tip (Manasi)
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Ville Syrjala <ville.syrjala@linux.intel.com>
Cc: Anusha Srivatsa <anusha.srivatsa@intel.com>
Cc: Lyude Paul <lyude@redhat.com>
Signed-off-by: Manasi Navare <manasi.d.navare@intel.com>
Reviewed-by: Lyude Paul <lyude@redhat.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20181206005407.4698-1-manasi.d.navare@intel.com
Define IS_GEN() similarly to our IS_GEN_RANGE(). but use gen instead of
gen_mask to do the comparison. Now callers can pass then gen as a parameter,
so we don't require one macro for each gen.
The following spatch was used to convert the users of these macros:
@@
expression e;
@@
(
- IS_GEN2(e)
+ IS_GEN(e, 2)
|
- IS_GEN3(e)
+ IS_GEN(e, 3)
|
- IS_GEN4(e)
+ IS_GEN(e, 4)
|
- IS_GEN5(e)
+ IS_GEN(e, 5)
|
- IS_GEN6(e)
+ IS_GEN(e, 6)
|
- IS_GEN7(e)
+ IS_GEN(e, 7)
|
- IS_GEN8(e)
+ IS_GEN(e, 8)
|
- IS_GEN9(e)
+ IS_GEN(e, 9)
|
- IS_GEN10(e)
+ IS_GEN(e, 10)
|
- IS_GEN11(e)
+ IS_GEN(e, 11)
)
v2: use IS_GEN rather than GT_GEN and compare to info.gen rather than
using the bitmask
Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20181212181044.15886-2-lucas.demarchi@intel.com
Adding a debug log when the DP_AUX_NATIVE_REPLY_ACK is missing
for aksv write. This helps to locate the possible non responding
DP HDCP sinks.
v2:
Rewritten for readability [Sean Paul]
Signed-off-by: Ramalingam C <ramalingam.c@intel.com>
Reviewed-by: Sean Paul <sean@poorly.run>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/1544010283-20223-4-git-send-email-ramalingam.c@intel.com
According to DP spec (2.9.3.1 of DP 1.4) if
EXTENDED_RECEIVER_CAPABILITY_FIELD_PRESENT is set the addresses in DPCD
02200h through 0220Fh shall contain the DPRX's true capability. These
values will match 00000h through 0000Fh, except for DPCD_REV,
MAX_LINK_RATE, DOWN_STREAM_PORT_PRESENT.
Read from DPCD once for all 3 values as this is an expensive operation.
Spec mentions that all of address space 02200h through 0220Fh should
contain the right information however currently only 3 values can
differ.
There is no address space in the intel_dp->dpcd struct for addresses
02200h through 0220Fh, and since so much of the data is a identical,
simply overwrite the values stored in 00000h through 0000Fh with the
values that can be overwritten from addresses 02200h through 0220Fh.
This patch helps with backward compatibility for devices pre DP1.3.
v2: read only dpcd values which can be affected, remove incorrect check,
split into drm include changes into separate patch, commit message,
verbose debugging statements during overwrite.
v3: white space fixes
v4: make path dependent on DPCD revision > 1.2
v5: split into function, removed DPCD rev check
v6: add debugging prints for early exit conditions
v7 (From Manasi):
* Memcpy, memcmp and debig logging based on sizeof(dpcd_ext) (Jani N)
* Exit early (Jani N)
v8 (From Manasi):
* Get rid of superfluous debug prints (Jani N)
* Print entire base DPCD before memcpy (Jani N)
v9 (From Manasi):
* Add uniform newlines (Rodrigo)
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Ville Syrjala <ville.syrjala@linux.intel.com>
Signed-off-by: Matt Atwood <matthew.s.atwood@intel.com>
Signed-off-by: Manasi Navare <manasi.d.navare@intel.com>
Tested-by: Manasi Navare <manasi.d.navare@intel.com>
Acked-by: Manasi Navare <manasi.d.navare@intel.com>
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20181129220058.19636-1-manasi.d.navare@intel.com
Always show the FEC capability as it is initialised to 0 before error.
Fixing,
drivers/gpu/drm/i915/intel_dp.c:3846 intel_dp_get_dsc_sink_cap() warn: inconsistent indenting
Fixes: 08cadae8e1 ("i915/dp/fec: Cache the FEC_CAPABLE DPCD register")
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Ville Syrjala <ville.syrjala@linux.intel.com>
Cc: Manasi Navare <manasi.d.navare@intel.com>
Cc: Anusha Srivatsa <anusha.srivatsa@intel.com>
Reviewed-by: Anusha Srivatsa <anusha.srivatsa@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20181120202439.13017-2-chris@chris-wilson.co.uk
Fix the intel_link_compute_m_n in case of display stream
compression. This patch passes the compressed_bpp to
intel_link_compute_m_n if compression is enabled.
Fixes: a4a157777c ("drm/i915/dp: Compute DSC pipe config in atomic check")
Cc: Ville Syrjala <ville.syrjala@linux.intel.com>
Cc: Anusha Srivatsa <anusha.srivatsa@intel.com>
Signed-off-by: Manasi Navare <manasi.d.navare@intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20181201010412.32372-1-manasi.d.navare@intel.com
For DP 1.4 and above, Display Stream compression can be
enabled only if Forward Error Correctin can be performed.
Add a crtc state for FEC. Currently, the state
is determined by platform, DP and DSC being
enabled. Moving forward we can use the state
to have error correction on other scenarios too
if needed.
v2:
- Control compression_enable with the fec_enable
parameter in crtc state and with intel_dp_supports_fec()
(Ville)
- intel_dp_can_fec()/intel_dp_supports_fec()(manasi)
v3: Check for FEC support along with setting crtc state.
v4: add checks to intel_dp_source_supports_dsc.(manasi)
- Move intel_dp_supports_fec() closer to
intel_dp_supports_dsc() (Anusha)
v5: Move fec check to intel_dp_supports_dsc(Ville)
v6: Remove warning. rebase.
v7: change crtc state to include DP sink and fec capability
of source.(Manasi)
v8: Set fec_enable in crtc in intel_dp_compute_config().
v9 (From Manasi):
* Combine the !edp and !fec_support check
* Derive dev_priv from intel_dp directly
v10 (From Manasi):
* Rebase
Suggested-by: Ville Syrjala <ville.syrjala@linux.intel.com>
Cc: dri-devel@lists.freedesktop.org
Cc: Ville Syrjala <ville.syrjala@linux.intel.com>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Manasi Navare <manasi.d.navare@intel.com>
Signed-off-by: Anusha Srivatsa <anusha.srivatsa@intel.com>
Signed-off-by: Manasi Navare <manasi.d.navare@intel.comk>
Reviewed-by: Manasi Navare <manasi.d.navare@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20181128202628.20238-14-manasi.d.navare@intel.com
This patch enables decompression support in sink device
before link training and disables the same during the
DDI disabling.
v3 (From manasi):
* Pass bool state to enable/disable (Ville)
v2:(From Manasi)
* Change the enable/disable function to take crtc_state
instead of intel_dp as an argument (Manasi)
* Use the compression_enable flag as part of crtc_state (Manasi)
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Ville Syrjala <ville.syrjala@linux.intel.com>
Cc: Anusha Srivatsa <anusha.srivatsa@intel.com>
Cc: Gaurav K Singh <gaurav.k.singh@intel.com>
Signed-off-by: Gaurav K Singh <gaurav.k.singh@intel.com>
Signed-off-by: Manasi Navare <manasi.d.navare@intel.com>
Reviewed-by: Anusha Srivatsa <anusha.srivatsa@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20181128202628.20238-6-manasi.d.navare@intel.com
This patches does the following:
1. This patch defines all the DSC parameters as per the VESA
DSC specification. These are stored in the encoder and used
to compute the PPS parameters to be sent to the Sink.
2. Compute all the DSC parameters which are derived from DSC
state of intel_crtc_state.
3. Compute all parameters that are VESA DSC specific
This computation happens in the atomic check phase during
compute_config() to validate if display stream compression
can be enabled for the requested mode.
v8 (From Manasi):
* DEBUG_KMS instead of DRM_ERROR for user triggerable
errors (Ville)
v7: (From Manasi)
* Dont use signed int for rc_range_params (Manasi)
* Mask the range_bpg_offset to use only 6 bits
* Add SPDX identifier (Chris Wilson)
v6 (From Manasi):
* Add a check for line_buf_depth return value (Anusha)
* Remove DRM DSC constants to different patch (Manasi)
v5 (From Manasi):
* Add logic to limit the max line buf depth for DSC 1.1 to 13
as per DSC 1.1 spec
* Fix dim checkpatch warnings/checks
v4 (From Gaurav):
* Rebase on latest drm tip
* rename variable name(Manasi)
* Populate linebuf_depth variable(Manasi)
v3 (From Gaurav):
* Rebase my previous patches on top of Manasi's latest patch
series
* Using >>n rather than /2^n (Manasi)
* Change the commit message to explain what the patch is doing(Gaurav)
Fixed review comments from Ville:
* Don't use macro TWOS_COMPLEMENT
* Mention in comment about the source of RC params
* Return directly from case statements
* Using single asssignment for assigning rc_range_params
* Using <<n rather than *2^n and removing the comments
about the fixed point numbers
v2 (From Manasi):
* Update logic for minor version to consider the dpcd value
and what supported by the HW platform
* Use DRM DSC config struct instead of intel_dp struct
* Move the DSC constants to DRM DSC header file
* Use u16, u8 where bigger data types not needed
* * Compute the DSC parameters as part of DSC compute config
since the computation can fail (Manasi)
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Ville Syrjala <ville.syrjala@linux.intel.com>
Cc: Anusha Srivatsa <anusha.srivatsa@intel.com>
Cc: Gaurav K Singh <gaurav.k.singh@intel.com>
Signed-off-by: Gaurav K Singh <gaurav.k.singh@intel.com>
Signed-off-by: Manasi Navare <manasi.d.navare@intel.com>
Co-developed-by: Manasi Navare <manasi.d.navare@intel.com>
Reviewed-by: Anusha Srivatsa <anusha.srivatsa@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20181129193827.7914-1-manasi.d.navare@intel.com
DSC params like the enable, compressed bpp, slice count and
dsc_split are added to the intel_crtc_state. These parameters
are set based on the requested mode and available link parameters
during the pipe configuration in atomic check phase.
These values are then later used to populate the remaining DSC
and RC parameters before enbaling DSC in atomic commit.
v15:
* Rebase over drm-tip
v14:
Remove leftovers, use dsc_bpc, refine dsc_compute_config (Ville)
v13:
* Compute DSC bpc only when DSC is req to be enabled (Ville)
v12:
* Override bpp with dsc dpcd color depth (Manasi)
v11:
* Const crtc_state, reject DSC on DP without FEC (Ville)
* Dont set dsc_split to false (Ville)
v10:
* Add a helper for dp_dsc support (Ville)
* Set pipe_config to max bpp, link params for DSC for now (Ville)
* Compute bpp - use dp dsc support helper (Ville)
v9:
* Rebase on top of drm-tip that now uses fast_narrow config
for edp (Manasi)
v8:
* Check for DSC bpc not 0 (manasi)
v7:
* Fix indentation in compute_m_n (Manasi)
v6 (From Gaurav):
* Remove function call of intel_dp_compute_dsc_params() and
invoke intel_dp_compute_dsc_params() in the patch where
it is defined to fix compilation warning (Gaurav)
v5:
Add drm_dsc_cfg in intel_crtc_state (Manasi)
v4:
* Rebase on refactoring of intel_dp_compute_config on tip (Manasi)
* Add a comment why we need to check PSR while enabling DSC (Gaurav)
v3:
* Check PPR > max_cdclock to use 2 VDSC instances (Ville)
v2:
* Add if-else for eDP/DP (Gaurav)
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Ville Syrjala <ville.syrjala@linux.intel.com>
Cc: Anusha Srivatsa <anusha.srivatsa@intel.com>
Cc: Gaurav K Singh <gaurav.k.singh@intel.com>
Signed-off-by: Manasi Navare <manasi.d.navare@intel.com>
Reviewed-by: Anusha Srivatsa <anusha.srivatsa@intel.com>
Reviewed-by: Ville Syrjala <ville.syrjala@linux.intel.com>
Acked-by: Jani Nikula <jani.nikula@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20181128213621.21391-1-manasi.d.navare@intel.com
When a PSR error happens sink sets the PSR error register and also
set the link status to a error status.
So in the short pulse handling it was returning earlier and doing a
full detection and attempting to retrain but it fails as PSR HW is
in change of the main-link.
Just call intel_psr_short_pulse() before
intel_dp_needs_link_retrain() is not the right fix as
intel_dp_needs_link_retrain() would return true and trigger a full
detection while PSR HW is still in change of main-link.
Check for PSR active is also not safe as it could be inactive due a
frontbuffer invalidate and still doing the PSR exit sequence.
v3: added comment in intel_dp_needs_link_retrain()
Cc: Dhinakaran Pandiyan <dhinakaran.pandiyan@intel.com>
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: José Roberto de Souza <jose.souza@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20181121225441.18785-2-jose.souza@intel.com
Some eDP panels do not set a valid sink count value and even for the
ones that sets is should always be one for eDP, that is why it is not
cached in intel_edp_init_dpcd().
But intel_dp_short_pulse() compares the old count with the read one
if there is a mistmatch a full port detection will be executed, what
was happening in the first short pulse interruption of eDP panels
that sets sink count.
Instead of just skip the compasison for eDP panels, lets not read
the sink count at all for eDP.
v2: the previous version of this patch it was caching the sink count
in intel_edp_init_dpcd() but I was pointed out by Ville a patch that
handled a case of a eDP panel that do not set sink count and as sink
count is not used to eDP certification was choosed to just not read
it at all.
Cc: Dhinakaran Pandiyan <dhinakaran.pandiyan@intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: José Roberto de Souza <jose.souza@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20181121225441.18785-1-jose.souza@intel.com
intel_dp_detect() caches the aux_domain in the beginning of the
function as it is used twice, so lets also use it as the aux_domain
don't change in runtime.
v3: returning intel_dp_retrain_link() error insted of
connector_status_disconnected
Cc: Imre Deak <imre.deak@intel.com>
Reviewed-by: Imre Deak <imre.deak@intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: José Roberto de Souza <jose.souza@intel.com>
Signed-off-by: Imre Deak <imre.deak@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20181107235449.32264-1-jose.souza@intel.com
The MG DP mode needs to be configured for Type C static/fixed/legacy
HDMI ports too, the same way as it's configured for Type C
static/fixed/legacy, fix this.
Bspec: 4232, 21735
Cc: Vandita Kulkarni <vandita.kulkarni@intel.com>
Cc: Paulo Zanoni <paulo.r.zanoni@intel.com>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Signed-off-by: Imre Deak <imre.deak@intel.com>
Reviewed-by: José Roberto de Souza <jose.souza@intel.com>
Tested-by: José Roberto de Souza <jose.souza@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20181102192656.4472-3-imre.deak@intel.com
The MG PHY clock gating needs to be configured for Type C
static/fixed/legacy HDMI ports the same way it's configured for Type C
static/fixed/legacy and aternate mode DP ports, fix this.
Bspec: 4232, 21735
Cc: Vandita Kulkarni <vandita.kulkarni@intel.com>
Cc: Paulo Zanoni <paulo.r.zanoni@intel.com>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Manasi Navare <manasi.d.navare@intel.com>
Signed-off-by: Imre Deak <imre.deak@intel.com>
Reviewed-by: José Roberto de Souza <jose.souza@intel.com>
Tested-by: José Roberto de Souza <jose.souza@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20181102192656.4472-2-imre.deak@intel.com
Similar to DSC DPCD registers, let us cache
FEC_CAPABLE register to avoid using stale
values. With this we can avoid aux reads
everytime and instead read the cached values.
v2: Avoid using memset and array for a single
field. (Manasi,Jani)
v3: Print FEC CAPABILITY value. (Manasi)
Suggested-by: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Ville Syrjala <ville.syrjala@linux.intel.com>
Cc: Manasi Navare <manasi.d.navare@intel.com>
Signed-off-by: Anusha Srivatsa <anusha.srivatsa@intel.com>
Reviewed-by: Manasi Navare <manasi.d.navare@intel.com>
Signed-off-by: Manasi Navare <manasi.d.navare@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20181102041455.15818-1-anusha.srivatsa@intel.com
Use the newly added "max bpc" connector property to limit pipe bpp.
V3: Use drm_connector_state to access the "max bpc" property
V4: Initialize the drm property, add suuport to DP(Ville)
V5: Use the property in the connector and fix CI failure(Ville)
V6: Use the core function to attach max_bpc property, remove the redundant
clamping of pipe bpp based on connector info
V7: Fix Checkpatch warnings
V9: Cleanup connected_sink_max_bpp and fix initial value in DP(Ville)
V12: Fix debug message(Ville)
V13: Remove the redundant check and simplify the check logic(Stan)
V14: Fix the check in connected_sink_max_bpp(Stan)
v15 (From Manasi): Add missing break (Stan)
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Kishore Kadiyala <kishore.kadiyala@intel.com>
Cc: Manasi Navare <manasi.d.navare@intel.com>
Cc: Stanislav Lisovskiy <stanislav.lisovskiy@intel.com>
Signed-off-by: Radhakrishna Sripada <radhakrishna.sripada@intel.com>
Reviewed-by: Stanislav Lisovskiy <stanislav.lisovskiy@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20181023014400.16055-1-manasi.d.navare@intel.com
From ICL onwards the AUX power domain may change dynamically based on
whether a DDI/TypeC port is in thunderbolt or non-thunderbolt mode, so
use a helper function instead of a static field to get the current
domain.
Cc: Paulo Zanoni <paulo.r.zanoni@intel.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: José Roberto de Souza <jose.souza@intel.com>
Cc: Lucas De Marchi <lucas.demarchi@intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: Imre Deak <imre.deak@intel.com>
Reviewed-by: José Roberto de Souza <jose.souza@intel.com>
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20181101140427.31026-5-imre.deak@intel.com
From ICL onwards DDI/TypeC ports - even in HDMI static mode - need to know
which AUX CH belongs to them, so initialize aux_ch for those ports too.
For consistency do this for all HDMI ports, not only for DDI/TypeC ones.
Cc: Paulo Zanoni <paulo.r.zanoni@intel.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: José Roberto de Souza <jose.souza@intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: Imre Deak <imre.deak@intel.com>
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20181101140427.31026-4-imre.deak@intel.com
From ICL onwards all DDI/TypeC ports - even working in HDMI mode - need
to know their corresponding AUX CH, so move the field to a common
struct.
No functional change.
v3:
- Add code comment about which ports aux_ch is used for. (Jose)
Cc: Paulo Zanoni <paulo.r.zanoni@intel.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: José Roberto de Souza <jose.souza@intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: Imre Deak <imre.deak@intel.com>
Reviewed-by: José Roberto de Souza <jose.souza@intel.com>
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20181101140427.31026-3-imre.deak@intel.com
From ICL onwards all the DDI/TypeC ports - even working in HDMI mode -
need to know their corresponding AUX channel, so move the corresponding
helper to a common place.
No functional change.
v4:
- Fix 'no space is necessary after a cast' checkpatch warn.
Cc: Paulo Zanoni <paulo.r.zanoni@intel.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: José Roberto de Souza <jose.souza@intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: Imre Deak <imre.deak@intel.com>
Reviewed-by: José Roberto de Souza <jose.souza@intel.com>
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20181101140427.31026-2-imre.deak@intel.com
Otherwise it would be in a inconsistent state as port is disconnected
but with a valid tc type.
Cc: Paulo Zanoni <paulo.r.zanoni@intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: José Roberto de Souza <jose.souza@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20181030215750.28213-3-jose.souza@intel.com
Otherwise it would be in a inconsistent state as port is disconnected
but with a valid tc type.
Also setting it to unknown will earlier return
icl_tc_phy_disconnect() for any future calls to
intel_digital_port_connected(), this way we don't need to check if
port is marked as safe everytime.
Cc: Paulo Zanoni <paulo.r.zanoni@intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: José Roberto de Souza <jose.souza@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20181030215750.28213-2-jose.souza@intel.com
When DSC is supported we need to validate the modes based on the
maximum supported compressed BPP and maximum supported slice count.
This allows us to allow the modes with pixel clock greater than the
available link BW as long as it meets the compressed BPP
and slice count requirements.
v3:
* Use the macro for dsc sink support (Jani N)
v2:
* Properly comment why we are right shifting the bpp value (Anusha)
Cc: Gaurav K Singh <gaurav.k.singh@intel.com>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Ville Syrjala <ville.syrjala@linux.intel.com>
Cc: Anusha Srivatsa <anusha.srivatsa@intel.com>
Signed-off-by: Manasi Navare <manasi.d.navare@intel.com>
Reviewed-by: Anusha Srivatsa <anusha.srivatsa@intel.com>
Reviewed-by: Gaurav K Singh <gaurav.k.singh@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20181031001923.31442-6-manasi.d.navare@intel.com
This patch adds helpers for calculating the maximum compressed BPP
supported with small joiner.
This also adds a helper for calculating the slice count in case
of small joiner.
These are inside intel_dp since they take into account hardware
limitations.
v6:
* Take mode_clock and mode_hdisplay as input arguments
so that this can be called in intel_dp_mode_valid (Manasi)
v5:
* Get the max slice width from DPCD
* Check against Min_Slice_width of 2560 (Anusha)
v4:
* #defines for PPR in slice count helper (Gaurav)
v3:
* Simply logic for bpp (DK)
* Limit the valid slice count by max supported by Sink (Manasi)
v2:
* Change the small joiner RAM buffer constant as bspec changed (Manasi)
* rename it as SMALL_JOINER since we are not enabling
big joiner yet (Anusha)
Cc: Gaurav K Singh <gaurav.k.singh@intel.com>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Ville Syrjala <ville.syrjala@linux.intel.com>
Cc: Anusha Srivatsa <anusha.srivatsa@intel.com>
Cc: Dhinakaran Pandiyan <dhinakaran.pandiyan@intel.com>
Signed-off-by: Manasi Navare <manasi.d.navare@intel.com>
Reviewed-by: Anusha Srivatsa <anusha.srivatsa@intel.com>
Reviewed-by: Gaurav K Singh <gaurav.k.singh@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20181031001923.31442-5-manasi.d.navare@intel.com
DSC is supported on eDP starting GEN 10 display (on GLK) and on DP starting
GEN 11.
This patch implements the discovery phase of DSC. On hotplug,
source reads the DSC DPCD register set (0x00060 - 0x0006F) to
read the decompression capabilities of the sink device.
This entire block of registers is cached in intel_dp so that
capability information can be used during DSC configuration
phase during compute_config phase of the modeset.
For eDP, this caching happens during the eDP initialization.
This caching is done only for eDP and DP rev >= 1.4
v5:
* Fix the block comment (Gaurav)
* Fix the commit message DSC DPCD addresses (Gaurav)
* Use DRM_ERROR for dpcd_read fail (Gaurav,Anusha)
v4:
* Cache these only for Gen >= 11
v3:
* Remove the dsc_sink_support field in intel_dp (Jani N)
v2:
* Clear the cached registers on hotplug always (Jani N)
* Combine the eDP and DP caching in same function (Jani N)
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Ville Syrjala <ville.syrjala@linux.intel.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Anusha Srivatsa <anusha.srivatsa@intel.com>
Cc: Gaurav K Singh <gaurav.k.singh@intel.com>
Signed-off-by: Manasi Navare <manasi.d.navare@intel.com>
Reviewed-by: Anusha Srivatsa <anusha.srivatsa@intel.com>
Reviewed-by: Gaurav K Singh <gaurav.k.singh@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20181031001923.31442-3-manasi.d.navare@intel.com
When a HDCP authentication is in progress, if the display sink is
hot unplugged, all DDC/AUX transaction related to the HDCP
authentication will fail.
This patch moves those kind of HDCP DDC/AUX failures into the debug
logs instead of errors.
v2:
Bksv invalid state is provided as debug msg
Signed-off-by: Ramalingam C <ramalingam.c@intel.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/1540291288-22185-1-git-send-email-ramalingam.c@intel.com
HDCP check link is invoked only on CP_IRQ detection, instead of all
short pulses.
v3:
No Changes.
v4:
Added sean in cc and collected the reviewed-by received.
v5:
No Change.
v6:
No Change.
v7:
No Change.
v8:
Rebased.
Signed-off-by: Ramalingam C <ramalingam.c@intel.com>
cc: Sean Paul <seanpaul@chromium.org>
Reviewed-by: Uma Shankar <uma.shankar@intel.com>
Reviewed-by: Sean Paul <seanpaul@chromium.org>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/1540286550-20399-3-git-send-email-ramalingam.c@intel.com
Just sorting this "if" block from newer to older platform.
The main difference here is the addition of a
missing case with return false that should never occur.
And if it occurs it is better than to raise a warn
than use the icl one.
The gen >= 11 was already present in the previous logic,
although hidden.
So, in summary no real functional change.
Cc: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20181022171526.15641-3-rodrigo.vivi@intel.com
Since when it was introduced we forgot to add
this case so ICL was using a wrong signal_levels
as reference.
Fixes: fb5c8e9d43 ("drm/i915/icl: Implement voltage swing programming sequence for Combo PHY DDI")
Cc: José Roberto de Souza <jose.souza@intel.com>
Cc: Manasi Navare <manasi.d.navare@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Reviewed-by: Manasi Navare <manasi.d.navare@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20181017215652.26841-1-rodrigo.vivi@intel.com
Another user of crtc->config gone. The functions it calls also
needed crtc->config, so convert those as well.
Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
[mlankhorst: Still pass m_n struct to intel_pch_transcoder_set_m_n (Ville)]
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20181011100457.8776-3-maarten.lankhorst@linux.intel.com
LSPCON chips can generate YCBCR outputs, if asked nicely :).
In order to generate YCBCR 4:2:0 outputs, a source must:
- send YCBCR 4:4:4 signals to LSPCON
- program color space as 4:2:0 in AVI infoframes
Whereas for YCBCR 4:4:4 outputs, the source must:
- send YCBCR 4:4:4 signals to LSPCON
- program color space as 4:4:4 in AVI infoframes
So for both 4:2:0 as well as 4:4:4 outputs, we are driving the
pipe for YCBCR 4:4:4 output, but AVI infoframe's color space
information indicates LSPCON FW to start scaling down from YCBCR
4:4:4 and generate YCBCR 4:2:0 output. As the scaling is done by
LSPCON device, we need not to reserve a scaler for 4:2:0 outputs.
V2: rebase
V3: Addressed review comments from Ville
- add enum crtc_output_format instead of bool ycbcr420
- use crtc_output_format=4:4:4 for modeset of LSPCON 4:2:0 output
cases in this way we will have YCBCR 4:4:4 framework ready (except
the ABI part)
V4: Added r-b from Maarten (for v3)
Addressed review comments from Ville:
- Do not add a non-atomic state variable to determine lspcon output.
Instead add bool in CRTC state to indicate lspcon based scaling.
V5: Addressed review comments from Ville:
- Change the state bool name from external scaling to something more
relavent.
- Keep the info and adjusted_mode structures const.
- use crtc_state instead of pipe_config.
- Push all the config change into lspcon_ycbcr420_config function.
V6: Rebase, small changes to accommodate changes in patch 2.
V7: Fixed checkpatch warnings for alignment
V8: Rebase
PS: Ignored following warnings to match the current formatting:
drm/i915: Add YCBCR 4:2:0/4:4:4 support for LSPCON
-:53: CHECK:SPACING: spaces preferred around that '<<' (ctx:VxV)
#53: FILE: drivers/gpu/drm/i915/i915_reg.h:8721:
+#define TRANS_MSA_SAMPLING_444 (2<<1)
^
-:54: CHECK:SPACING: spaces preferred around that '<<' (ctx:VxV)
#54: FILE: drivers/gpu/drm/i915/i915_reg.h:8722:
+#define TRANS_MSA_CLRSP_YCBCR (2<<3)
V9: Rebase
V10: Rebase
V11: Rebase
Cc: Ville Syrjala <ville.syrjala@linux.intel.com>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Reviewed-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Signed-off-by: Shashank Sharma <shashank.sharma@intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/1539325394-20788-8-git-send-email-shashank.sharma@intel.com
This patch adds an enum "intel_output_format" to represent
the output format of a particular CRTC. This enum will be
used to produce a RGB/YCBCR4:4:4/YCBCR4:2:0 output format
during the atomic modeset calculations.
V5:
- Created this separate patch to introduce and init output_format.
- Initialize parameters of output_format_str respectively (Jani N).
- Call it intel_output_format than crtc_output_format(Ville).
- Set output format in pipe_config for every encoder (Ville).
- Get rid of extra DRM_DEBUG_KMS during get_pipe_config (Ville)
V6: Rebase
V7: Fixed alignment warnings (checkpatch)
V8: Another check[atch warning for alignment
V9: Rebase
V10: Rebase on top of DSI restructure
V11: Addressed review comment from Ville
- Set CRTC format for pre-HSW get_pipe_config() function too.
Added Ville's R-B
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Shashank Sharma <shashank.sharma@intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/1539325394-20788-1-git-send-email-shashank.sharma@intel.com
This patch fixes the original commit c0cfb10d9e ("drm/i915/edp:
Do not do link training fallback or prune modes on EDP") that causes
a blank screen in case of certain eDP panels (Eg: seen on Dell XPS13 9350)
where first link training fails and a retraining is required by falling
back to lower link rate/lane count.
In case of some panels they advertise higher link rate/lane count
than whats required for supporting the panel's native mode.
But we always link train at highest link rate/lane count for eDP
and if that fails we can still fallback to lower link rate/lane count
as long as the fallback link BW still fits the native mode to avoid
pruning the panel's native mode yet retraining at fallback values
to recover from a blank screen.
v3:
* Add const for fixed_mode (Ville)
v2:
* Send uevent if link failure on eDP unconditionally
Fixes: c0cfb10d9e ("drm/i915/edp: Do not do link training fallback or prune modes on EDP")
Cc: Clinton Taylor <clinton.a.taylor@intel.com>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Ville Syrjala <ville.syrjala@linux.intel.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Lucas De Marchi <lucas.demarchi@intel.com>
Cc: <stable@vger.kernel.org> # v4.17+
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=107489
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=105338
Signed-off-by: Manasi Navare <manasi.d.navare@intel.com>
Tested-by: Alexander Wilson <alexander.wilson@ncf.edu>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20181009212804.702-1-manasi.d.navare@intel.com
Almost all of the connector destroy functions do the same thing. The
differences are in the edid, detect_edid and panel cleanups, but those
are safely NULL when not initialized. Roll out a common connector
destroy hook.
Inspired by commit bc3213c444 ("drm/i915: Drop the eDP check from
intel_dp_connector_destroy()").
Cc: Ville Syrjala <ville.syrjala@linux.intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20181009141103.20387-1-jani.nikula@intel.com
As long as the connector was zeroed during allocation calling
intel_panel_fini() is safe even if we haven't initialized
the panel struct explicitly. So let's drop the useless eDP
check from dp connector destruction.
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20181008134641.24868-2-ville.syrjala@linux.intel.com
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Always print out the information whether the port and sink can each
do MST. And let's include the modparam in the debug output as well.
Makes life a little less confusing when you don't have to wonder
why MST isn't kicking in.
This does cause a slight change in our behaviour towards the sink.
Previously we only read the MSTM_CAP register after passing all
the other checks. Now we will read that register regardless. Hopefully
some crazy sink doesn't get confused by a simple register read.
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20181003184210.1306-1-ville.syrjala@linux.intel.com
Reviewed-by: Dhinakaran Pandiyan <dhinakaran.pandiyan@intel.com>
